I haven't seen any posts mentioning swing speed, yet that seems to be a pretty fundamental - perhaps the major - criterion in choice of ball, as it is in choice of shaft flex, for similar reasons. Basically, the fastest swings do best with the hardest balls; the slower the swing, the softer the ball should be. This is based on the amount of power it takes to compress the ball optimally, since DEcompression adds to ball speed off the club, resulting in distance. No compression, no decompression - just plain physics. BTW, another factor's temperature, which also affects compression/resiliency: the colder the day, the softer the ball should be.
I'm 73, and my HCP's up to 17; I was never great, but not so many years ago I was still playing 12-14. But now, I don't have anywhere near the swing speed I used to have. I used to play Titleist V1's (the V1x was always too hard) or similar (and used R steel shafts). A few years ago, when my game was deteriorating, a pro suggested Senior graphite shafts and softer balls. First, I switched shafts, with pleasing results. Then, with those shafts, I compared the V1's to the softer balls, and the latter felt and were markedly better - incidentally, control (I've been battling a slice since I was a pup, but usually have it pretty much under control, until I get tired and lose concentration) is usually better, too. Now, I like Bridgestone's B330-RX and RXS best. But their e6, and the DT Solo, aren't far behind, and are a lot cheaper. And, BTW, good ladies's balls are pretty good, too. The brands differ, IMO, primarily with regard to hook/slice control, and stopping, on approach shots, and my experience is that Bridgestone's best for me.
Altogether, my opinion is that most of us who aren't single-handicappers - and that's probably most of us - can't use balls like the V1x effectively, any more than we can use stiff shafts, and probably would do best with balls even softer than the V1.